Mercaptoacyl derivatives of proline and 4-hydroxyproline are disclosed as useful antihypertension agents due to their angiotensin converting enzyme inhibition activity in U.S. Pat. No. 4,105,776 on Ondetti et al.
Mercaptoacyl derivatives of proline wherein the acyl sidechain can be substituted by an alkyl or trifluoromethyl group and the proline can be substituted with one or more halogens are also useful as angiotensin converting enzyme inhibitors as note Ondetti et al. U.S. Pat. No. 4,154,935.
Mercaptoacyl 3,4-dehydroprolines are disclosed as useful antihypertension agents due to their angiotensin converting enzyme inhibition activity in U.S. Pat. No. 4,129,566 of Ondetti et al.
Mercaptoacyl derivatives of proline wherein the acyl sidechain can be substituted with a lower alkylthio group are also disclosed as angiotensin converting enzyme inhibitors by Ondetti et al. in U.S. Pat. No. 4,116,962.